Kate Bosworth is the most famous example of someone with heterochromia iridum, which manifests as a difference in coloration between the two eyes (for example one eye blue and one eye brown) or variation only in degree (such as a lighter or darker hue). This condition is also known as ocular Mitchell-Riffel syndrome. That said, there are fewer than 100 documented cases.
Kate Bosworth was born with both eyes different colors. Her left/non-dominant eye’s iris is hazel while her right’s is green, which makes for some interesting photos ops! Anyways; this genetic anomaly isn’t limited to just people- it can happen in animals too like cats